Total pressure exerted by a gas mixture = sum of partial pressure of individual gases
Pertinent to the composition of alveolar gas
Governs the exchange of gases between alveoli and blood during external respiration
Henry's Law
Amount of gas dissolved in a liquid is proportional to its partial pressure and solubility
Dictates the exchange of gases between alveolar air and blood
Regulates the dissolution of gases in blood plasma during internal respiration
How oxygen is transported in blood
1.5% dissolved in plasma
98.5% bound to hemoglobin in RBCs
Hemoglobin's affinity for oxygen
Changes based on temperature, partial pressure of carbon dioxide (PCO2), blood pH, production of bisphosphoglyceric acid (BPG) from glycolysis
Oxygen-hemoglobin dissociation curve
Demonstrates hemoglobin's affinity for oxygen
Relatively flat at high partial pressure of oxygen
Low PO2 = hemoglobin releases oxygen to tissue, especially during exercise
During vigorous exercise = more oxygen is unloaded to tissues despite high plasma PO2 levels
Types of hypoxia
Anemic hypoxia
Ischemic hypoxia
Histotoxic hypoxia
Hypoxemic hypoxia
Carbon monoxide poisoning
Caused by carbon monoxide binding to hemoglobin with greater affinity than oxygen
Reduces the blood's oxygen-carrying capacity
How carbon dioxide is transported in the blood
Dissolved in plasma (7-10%)
Bound to hemoglobin (20%)
Bicarbonate ions (HCO3-) (majority)
Conversion of CO2 to bicarbonate ions
1. CO2 combines with water and dissociates, producing carbonic acid and bicarbonate ions that can release or absorb H+
2. Chloride ions move into RBC to maintain charge balance ("chloride shift")
PO2
Controls perfusion by changing arteriolar diameter
Optimizes perfusion and maximizes oxygen uptake into the blood
Low PO2 in muscles during exercise, hemoglobin easily releases oxygen to body tissues
High plasma partial pressures of oxygen, hemoglobins unloads little oxygen
During vigorous exercise, plasma partial pressure of oxygen falls dramatically so much more oxygen can be unloaded to the tissues
PCO2
Controls ventilation by changing bronchiolar diameter
Increases ventilation so there can be more rapid release of CO2
Carbonic acid-bicarbonate buffer system of the blood is formed when CO2 combines with water and dissociates, producing carbonic acid and bicarbonate ions that can release or absorb H+
Slow, shallow breathing
Causes an increase in CO2 in blood resulting in a drop in pH
Rapid, deep breathing
Causes a decrease in CO2 in blood, resulting a rise in pH